Improvement in whiffletree-centers



UNITED STATES PATENTQEECE- HENRY PORTER, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN WHIFFLETREE-CENTERS.

Specification forming part of Letters Patent No. 156,432', datedNovember 3, 1874; application filed March 2e, 1874.

To all whom it may concern:

Be it known that I, HENRY K. PORTER, of Boston, in the county of Suffolkand State of Massachusetts, have invented a new and useful Whiflietree-Center, of which the following is a specification:

The invention consists in the peculiar construction of the locks of thepivot irons or circles, so that they are cast complete and ready for usewithout iinishing, and yet possess all the desired advantages of thosewhich are constructed at much greater cost, and which are wrought intoform by expensive processes.

Figure l is a vertical Y,section taken on line W X, Fig. 3, and line UV, Figs. 4, 5, and 6, and shows the halves of the circle when united,the line of this section being in the direction of the axis of thewhifdetree. Fig. 2 is also a vertical section, taken on the lines Q R ST and Y Z of Figs. 3, 4, 5, and 6. Fig. 3 is a bottom side or plan viewof A. Fig. 4 is a top side or plan view of B. Fig. 5 is a top side orplan view of A. Fig. 6 is a bottom side or plan view ot B.

A is the half of the circle, which is attached to the whifietree; and B,that which is secured to the cross-bar by screws, as shown at u. a isthe hole for the bolt; and b is a concentric ange formed upon B, andwhich fits into the circulai` recess formed in A. (Shown in Figs. 1 and2, and marked cin Fig. d d are flanges forming segments of a circle, apart, as shown inside dotted line g, being cut away for the purposehereinafter stated. f f are apertures corresponding to but slightlylarger than flanges d, and cut through bed A, so that when molded -forcasting, the sand beneath ianges d d and between its lower` plane andthe-upper plane of the main bed, as shown f in Fig. 3, shall besupported by that in recesses f, and allow the withdrawal of thepattern, yet leaving the perfect sand-mold beneath the flanges. h, Figs.1, 2, and 6, represents a thin bar extending across the aperture incircle B, the circular flange or thimble b being formed upon this bar. ii are two segmentary flanges, formed flush with the top of the circle orplate B, as shown in Fig. 2. The dotted line k, Fig. 4, shows the partof this circular iiange which is cut away for the purpose hereinafterstated. j j are apertures directly beneath but slightly larger thanflanges M, and which constitute the space between bar h and the circularspace cut in the main bed. The object of these spaces j is the same asthe spaces f fin circle A, as before eX- plained.

For the purpose of uniting these two halves of the circle, one half isrotated horizontally ninety degrees relatively to the other, when theflanges d d of plate A will occupy the space la, cut away between angesi i, plate B, and

the ijanges i will occupy the spaces g, cut` away between the iianges din plate A, thereby allowing the main plates to be brought together,when, by rotating one of the plates ninety degrees, the iianges d d andi i will be locked each behind the other, as shown in Fig. 2, while thecircular ange b serves to prevent all lateral motion.

By this peculiar construction Iam enabled to cast, perfect and iinished,a centrally-pivoted and most safely-locking circle, without increase ofexpense over the most unsafe kind.

Having thus described my invention, what I claim ish A whiflietreecircle or center consisting of the combined parts A B, formedrespectively with the flanges d d and t' c', and the apertures f f and jj, substantially as described and shown.

HENRY K. PORTER.

Witnesses EBEN HUTcHINsoN, SAML. W. CLARKE.

